Many programs that display forms include an “autofill” function that will store inputs to a form field. This is a common feature of web browsers. Popular web browsers that include some autofill functionality include Internet Explorer® (registered trademark of Microsoft Corporation) and Safari® (registered trademark of Apple Inc.). When a user encounters the same form field again and begins to enter characters into the field, the web browser will display some or all of the previous entries for this field, typically in a drop-down menu, and allow the user to select one of the displayed entries to populate the field.
The autofill functionality typically narrows down the list of displayed previous user entries to those that begin with the characters the user has entered so far into the field. As an example, a user may use several email accounts to receive information from different websites. When the web browser is displaying a web page received from a website that is requesting an email address, the user mouse-clicks in the email address form field and the web browser displays all email addresses that have been entered in any email address form field at any website with that browser. As the user begins entering an email address, the list of displayed previously entered email addresses is first narrowed to those email addresses that begin with the first character the user has entered, then is narrowed to email addresses that begin with the first two characters entered, and so on. If the user is entering an email address that has not been used before in an email address form field, then at some point there will not be a match to any previously entered email addresses. When this occurs, no matching previously entered email addresses will be displayed and the browser will typically store the new email address entry. At any time, the user may select one of the displayed previously entered email addresses to populate the field, or select the “enter” key to populate the field with the characters entered so far.